chore: Don't require envs in build time, and load them dynamically

[patrick11514]

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[Copilot]

Pull request overview

This PR refactors environment variable management by moving from SvelteKit's static environment imports ($env/static/private) to dynamic imports ($env/dynamic/private) with centralized validation using Zod. This change allows environment variables to be loaded at runtime rather than at build time, making the application more flexible for different deployment environments.

Changes:

• Created a new centralized env.ts module with Zod schema validation for all environment variables
• Migrated all files using $env/static/private to import from the new env module
• Removed parseInt calls where Zod's z.coerce.number() now handles string-to-number conversion

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/lib/server/env.ts	New file that defines and validates environment variables using Zod schema, providing type-safe access to configuration
src/lib/server/variables.ts	Updated to use the new centralized env module instead of static env imports
src/lib/server/nina.ts	Removed default fallback logic as defaults are now handled by Zod schema
src/lib/server/functions.ts	Updated to import FILE_FOLDER from the new env module
src/routes/image/[name]/+server.ts	Updated to import FILE_FOLDER from the new env module and reorganized imports
src/lib/server/_routes/upload.ts	Updated to import FILE_FOLDER from the new env module and reorganized imports
src/lib/server/_routes/login.ts	Updated to import COOKIE_EXPIRE from the new env module
src/lib/server/_routes/article.ts	Updated to import FILE_FOLDER from the new env module
src/lib/server/_routes/ai.ts	Updated to import GEMINI_API_KEY from the new env module